1. Field Of The Invention
The present invention relates to a chromatographic device for the simultaneous collection and evaporation of sequential volatile non-aqueous eluates. More particularly, the device is concerned with the integration of collection and evaporation steps by gearing the rate of collection to the rate of evaporation and increasing the surface area available for evaporation. As samples are collected, they can be continuously introduced directly to the evaporation step without the need for intermittent transfer of batches to the evaporation process.
2. Description Of The Prior Art
The ability to reliably analyze large numbers of volatile samples of chromatographic eluates has been limited by a chromatographic step which requires the collection of eluting solvent before its subsequent evaporation. This evaporation can take as much as 4-fold longer than the collection process and, in some cases, requires a transfer step involving additional glassware. This cumbersome procedure contributes to losses and possible contamination of the sample.
Typical prior art devices are characterized by Organomation's N-EVAP. Said device is comprised of a housing for a water bath in which are inserted numerous tubes containing the eluate to be evaporated. Above each tube is a nitrogen outlet connected to a manifold, which allows for the nitrogen to contact the material in each tube, thereby causing the volatile solvent to evaporate, leaving behind the sample to be analyzed.
The principle problems with the prior art devices have been the length of time necessary to carry out the collection and evaporation, the tendency of the sample to become contaminated during transfer to the evaporation medium, the availability of only a small surface area for evaporation and the inability to correlate the rate of collection with the rate of evaporation.
In accordance with the present invention, a chromatographic device for the simultaneous collection and evaporation of sequential volatile organic eluates is described wherein the collection process is integrated with the evaporation process and correlated therewith so that the collection and evaporation can be carried out in a rapid and efficient manner. Said device increases the surface area available for evaporation, eliminates contamination, allows for as much as a 5-fold reduction in the time necessary to carry out the process, allows for evaporation of and analysis of several samples from the same batch, a procedure which, in certain cases, would otherwise be too labor intensive to be practical, and allows for the evaporation of larger volumes than the volume of the evaporating vessel.